[A case of progressive supranuclear palsy with progressive non-fluent agrammatic variant primary progressive aphasia who could sing fluently].

The patient was a 65-year-old man. He visited the hospital complaining of gait disturbances and difficulty speaking. He was diagnosed with progressive supranuclear palsy because of slow vertical eye movements, frequent falls, and freezing gait; these symptoms were levodopa-resistant. The patient also had aphasia similar to non-fluent agrammatic variant of primary progressive aphasia, stuttering, and palilalia. However, he was able to sing a familiar song fluently. In contrast, for an unfamiliar song, he could not begin singing without the lyrics, and was more accurate at reading aloud than singing. Nonfluent aphasia with preserved singing ability has been reported in patients with stroke and trauma. However, this has rarely been reported for neurodegenerative diseases. This phenomenon may be due to the functional preservation of the right hemisphere and the left temporal lobe. The familiar song may have been stored in long-term memory as a set of lyrics and melody, and he may have produced it as automatic language.